HELP!!!! I researched Science Buddies for my science fair project idea and chose Electrolyte Challenge: Orange Juice VS Sports Drinks and added a few of my own ideas. My question is I am not sure why the example of this project uses tap H2O and distilled H2O as the study is looking at the electrolyte levels from orange juice vs sport drinks? Please help shed some light. I did the experiment and used OJ, Powerade, and Gatorade and I did follow all of the steps in the example project on Science Buddies. I am not real sure why the project tested tap/distilled water. Help!!! I am analyzing my data and putting charts and graphs together to hand in January 7, 2014, 2 days from now. I want to have a sound understanding of the entire project.

oliveoil3 - The testing of distilled and tap water help establish a baseline comparison for yor analysis of the sports drink. The distilled water has very few ionized elements and will register a near 'zero' measurement. Tap water may contain many many other dissolved minerals and other 'ionized' components, and register a low reading, but nothing even close to the sports drink. It serves as a measured comparison to your sports drink observations. It is like a 'control' element.

Thank you Mark for your quick response. I thought maybe it would be a baseline but was not sure. You are correct, the distilled H2O does not show any data on the bar graph that I used to show my results. The tap water shows some electrolytes. OJ registered the greatest amount of electrolytes. I also asked an additional question under a new topic concerning the same study. If you have time, could you look at the additional question and let me know your thoughts. Thanks again, I really appreciate your time.

oliveoil3 - Your measurements are very consistent with the results I obtain when doing this experiment. I'm not sure what your other question was as this topic seems to be several threads that are very different, starting out with a reference to a deadly disease, then changing to the buoyancy of an egg in seawater, then your question about the electrolyte experiment. How can I help?

Thanks for your quick response. I just tagged my question on to the quick response. I was not sure what format to use to ask my questions. My question regarding the electrolyte project has nothing to do with the other topics. I just rode on their coat tails for a "quick response". Thank you. I also wanted to know if my data seemed accurate. You indicated that it does. I wanted your opinion for a few other questions. Is the controlled variable for the elecrtrolyte project the 200 microamps for distilled water and 200 milliamps for all other drinks? Would the independent variable be the different liquids used for the experiment? I used the same liquids for each test(all at room temperature), orange Gatorade, orange PowerAde, and Orange Juice. I would not include tap/distilled water for an independent variable since tat is the baseline, right? I am just not sure how to address the tap/distilled water other than they were used as a baseline. The third variable I am looking for is the dependent variable. Would the dependent variable be the amount of electrolytes found in each liquid? I had to do two conversions to solve for the conductance also known as the Siemens or electrolytes. I feel it is important to show the judges the two conversions to solve for the electrolyte levels. First I had to convert the data to amps. Second I had to convert the amps to Siemens/electrolytes by using the formula G (Siemens)=current divided by voltage. Please keep in mind that I conducted 10 trials. I tested all 5 liquids with the meter 10 different times. In between each test, I washed and rinsed the bowls with distilled water. I was careful not to contaminate any part of the testing process. Your thoughts???

oliveoil3 - I think your procedures were very precise so you should have a well documented experiment. In this case, you are measuring conductance of the electrolyte (the reciprocal of resistance). I would say that the independent variable is the electrical current setup made up of the battery and current sensing resistance, internal to the multimeter. The dependent variables would be the results that indicate a wide range of conductance values from your various electrolytes. In that you have been meticulous in your procedure it should be mentioned that my changing the range setup of the multimeter, say from 200 microamps to 200 milliamps, the internal resistance of the multimeter shunt probably varies, so you don't have a perfectly constant independent variable. To eliminate that variable, try to do all your measurements using the same multimeter range, the 200 milliamp range. In addition, the battery terminal voltage can change with use, again changing, even slightly, the independent variable. This experiment tends to ignore those small differences, but they can effect your measurements so you might want to discuss in your experiment written document. Good luck, good work.